The Vibrational and Electronic Spectra of Cyanoacetylene

Abstract

<p> The infrared and Raman spectra of cyanoacetylene and deuterocyanoacetylene have been measured and ground state vibrational energy levels have been obtained from the analysis of these spectra.</p> <p> Two band systems have been identified in the absorption spectrum of cyanoacetylene in the region 2700 - 2000 Å. Vibrational and rotational analyses have shown that the lower energy transition involves a non-linear planar upper state having A" symmetry. Approximate geometry of the molecule in the A" state has been determined.</p> <p> In the second electronic transition the upper state has been found to be linear. A vibrational analysis has been obtained on the basis of an electronically forbidden 1Δ<--- 1 Σ+ or 1 Σ- <--- 1 Σ+ transition, which is made allowed by vibronic interactions.</p>